Video Formats

video works with electronics and magnetism in stead of using light to generate an image unlike film there are different formats around the world
In the UK we use PAL which stands for Phase Alternating Line it runs at 25 frames per second it is 768 across by 576 pixels in height when it uses the 4:3 aspect ratio using square pixels using domestic equipment it uses 720 by 576 using rectangular pixels.
IN the USA they use NTSC which stands for National Television System Committee it runs at 29.97 frames per second it is 640 across by 480 pixels in height when it using the 4:3 aspect ratio on tv and for home use 720 by 480

in europe SECAM is used which stands for Séquentiel couleur à mémoire, French for Sequential Color with Memory it runs at 25 frames per second like PAL its frame size is 768 by 546 at 4:3 with square pixels on domestic equipment it uses 720 by 546 

pal has a crisper more detailed image but its movement isn't as good quality on NTSC the quality is lower but the frame rate give better movement


In hd PAL SECAM and NTSC the frame rates are still the same but the frame sizes are universal now 
it is now 1920 by 1080 
this is called 1080p or 1080i 

p stands for progressive this means that all 1080 lines are shown at the same time 

i stands for interlaced where it splits the shot in half and only one half is shown at a time but it happens that quick that people don't notice.  interlaced footage processes quicker this means that interlaced tvs are cheaper to produce.